I have a 1990 GMC K1500, stalling issues.
the truck will start up most time fine with a little gas, after about 30 seconds in idle it will do an
irregular idle and then stall out. Also when I put the truck into reverse or drive without my foot on the
gas pedal it will stall out. I can drive the truck as long as my foot is on the pedal giving it a little gas
when I'm at a stop light.
So far I have replace the IAC, PT sensor, ECS module, Ignition module, spark plugs, distributor cap and
wires, fuel pump relay, fuel filter, i have cleaned the carburetor with cleaner spray.Please help!!
Have you tested the fuel pressure? Sounds like the pump is dying.
So, I changed my fuel filter again and it's running much better but is still stalling, I haven't done a fuel pressure test yet but while I was under changing the fuel filter I saw a pretty major exhaust crack. Do you think this has something to do with the symptoms?
If the exhaust was bent I'd say yea but no not a hole. I'm still betting on the pump.
Bloomington ca.... I have a 90 GMC 1500 5.7 have almost the same problems i dont have the same problem but i dont need to keep my foot on the peddle when you punch it too fast the idle drops and stalls cause its in a high idle i have everything brand new but the fuel pump i was told that it could be the computer i replaced it and its still doing the same thing i took it the mechanic and he had it on computers i was told it was the transmission can i took it to the transmission shop and its okay i was told it could be the wire harness it could be a short so i look at it and still havent found anything yet.... im still stuck on it im getting ready to get rid of the truck!!!
What is your fuel pumps pressure
same here, but my fuel shoots 6 to 8 inches across intake when pump is running. i tried this when throttle body was off. i just replaced fuel pump, fuel filter, new injectors, computer, coil, alt, egr valve, checked every vacuum line and intake for leaks, and it idles fine but soon as rpm gets about 1500 it cuts out really bad and if i floor it it will surge from barely running to high rpm. i cant drive over 35 mph. and would a mufflef that has a bend sideways in it cause this?
Yes a bent exhaust will act exactly like a clogged catalytic converter, light throttle at low rpm is fine but full throttle or higher rpm and the engine can't exhale, it's like trying to hold your breath and suck in more air, eventually you won't have room for more air in your lungs and you can't hold your breath forever. Just unbolt the exhaust and see if it solves your problem.
An engine under a heavy load consumes about 50% more air than it would in neutral being revved.
now when i wiggle the wiring harness going from inner firewall to computer it stops acting bad for a second, but returns back, i have checked every wire in the harness and found no cracks or any broken or frayed wires. all the plugs look good and hold tight, could it be a bad ground somewhere
You may not see a fault in the wire but it could still be there, I spent quite some time chasing down a bad wire for the ac compressor. Found a hunk of wire that had corroded from the inside, not sure if the wire was nicked or if it got moisture in it when it was made but there was about a quarter inch of the inside that was just a green/white clump of dust. Couldn't find anything wrong with the insulation.
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